Summary

• Problem: extensions/diffs/index.test.ts throws TypeError: Cannot read properties of undefined (reading 'x-forwarded-for') in the applies plugin-config defaults test case.
• Why it matters: Every open PR currently fails the checks (node, extensions) CI job due to this, even when the PR doesn't touch extensions code. Blocks merge readiness assessment for unrelated PRs.
• What changed: Added headers: {} to the localReq() mock helper so hasProxyForwardingHints() can safely access req.headers.
• What did NOT change: No production code touched. Only the test mock helper in index.test.ts. The identical localReq() helper in http.test.ts already has this property (added in 44881b0).

Change Type (select all)

• Bug fix
• Feature
• Refactor
• Docs
• Security hardening
• Chore/infra

Scope (select all touched areas)

• Gateway / orchestration
• Skills / tool execution
• Auth / tokens
• Memory / storage
• Integrations
• API / contracts
• UI / DX
• CI/CD / infra

Linked Issue/PR

• Related: 44881b0 (introduced hasProxyForwardingHints(), updated http.test.ts but missed index.test.ts)
• Unblocks: fix(agents): warn on unrecognised model ID instead of silently falling back #38631, fix(feishu): extract content from interactive card variants when quoting #38776, fix(feishu): preserve sender identity and resolve mentions in merge_forward messages #39001 (and all other open PRs failing extensions CI)

User-visible / Behavior Changes

None. Test-only change.

Security Impact (required)

• New permissions/capabilities? No
• Secrets/tokens handling changed? No
• New/changed network calls? No
• Command/tool execution surface changed? No
• Data access scope changed? No

Repro + Verification

Environment

• CI runner (Ubuntu, node)
• Reproducible on any branch based on main after 44881b0

Steps

1. Open any PR targeting main
2. Wait for checks (node, extensions, pnpm test:extensions) CI job
3. Observe failure in extensions/diffs/index.test.ts

Expected

All 258 extension test files pass (2260 tests).

Actual

1 test file fails, 257 pass. The specific failure:

TypeError: Cannot read properties of undefined (reading 'x-forwarded-for')
 at hasProxyForwardingHints  extensions/diffs/src/http.ts:180:9
 at resolveViewerAccess      extensions/diffs/src/http.ts:193:58
 at                          extensions/diffs/index.test.ts:124:27

Evidence

Before (from PR #38631 CI run 22803165182):

FAIL extensions/diffs/index.test.ts > diffs plugin registration > applies plugin-config defaults
TypeError: Cannot read properties of undefined (reading 'x-forwarded-for')
Test Files  1 failed | 257 passed (258)
Tests       1 failed | 2258 passed | 1 skipped (2260)

After (PR #39047 CI run 22803786316):

checks (node, extensions, pnpm test:extensions)  pass  1m57s

Human Verification (required)

• Verified the localReq() helper in http.test.ts:235-244 already includes headers: input.headers ?? {} as the established pattern from the same commit (44881b0)
• Confirmed index.test.ts's localReq() is the only other mock helper that was missed
• Checked the full index.test.ts file: localReq() is called once (line 125), always with { method, url }, never needs custom headers
• CI confirms fix: extensions job now passes on this PR

Compatibility / Migration

• Backward compatible? Yes
• Config/env changes? No
• Migration needed? No

Failure Recovery (if this breaks)

• Revert this single commit
• Zero risk: only adds an empty object to a test mock

Risks and Mitigations

None. Single-line addition to a test helper with no production code impact.